Absorption of carbon dioxide into aqueous blends of diethanolamine and methyldiethanolamine

In this work, a comprehensive model is developed for the absorption of carb on dioxide into aqueous mixtures of primary or secondary alkanolamines with tertiary alkanolamines. The model, which is based on penetration theory, i ncorporates an extensive set of important reversible reactions and takes in to account the coupling between chemical equilibrium, mass transfer, and ch emical kinetics. The reaction between CO2 and the primary or secondary amin e is modeled according to the zwitterion mechanism. The key physicochemical properties that are needed for the model are the CO2 physical solubility, the CO2 and amine diffusion coefficients, and the reaction rate coefficient s and equilibrium constants. Data for carbon dioxide absorption into aqueou s mixtures of diethanolamine and methyldiethanolamine are compared to model predictions.